Process for producing organically modified oxide, oxynitride or nitride layers by vacuum deposition

ABSTRACT

Method for producing at least one organically-modified oxide, oxinitride or nitride layer by vacuum coating on a substrate through plasma-enhanced evaporation of evaporation material comprising nitride-forming evaporation material and one of oxide and suboxide evaporation material, wherein the at least one layer is deposited through plasma-enhanced, reactive high-rate evaporation of the evaporation material with use of gaseous monomers and a reactive gas including at least one of oxygen and nitrogen, and wherein the evaporation material, gaseous monomers, and reactive gas pass through a high-density plasma zone immediately in front of the substrate. A method for producing at least one organically-modified oxide, oxinitride or nitride layer by vacuum coating on a substrate through plasma-enhanced evaporation of one of oxide and suboxide evaporation material, wherein the at least one layer is deposited through plasma-enhanced, reactive high-rate evaporation of the evaporation material with use of gaseous monomers and a reactive gas including at least one of oxygen and nitrogen, and wherein the evaporation material, gaseous monomers, and reactive gas pass through a high-density plasma zone immediately in front of the substrate. Substrates with an organically-modified oxide, oxinitride or nitride layer, as produced by the methods, wherein the at least one layer deposited by plasma-enhanced, high-rate vapor deposition includes more than 50 wt% of inorganic molecules and less than 50 wt% of partially cross-linked organic molecules.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method for producing organically-modifiedoxide, oxinitride or nitride layers on large areas through vacuumcoating. Preferred applications of these layers are transparent barrierfilms for packaging materials and transparent corrosion-protective oranti-abrasion layers for window faces, mirrors, decorative surfaces, orfacade coatings.

2. Discussion of Background

It is known to produce layers for these applications by varnishing withtransparent varnish layers or laminating transparent plastic films.Although an adequate barrier or corrosion-protective effect can beobtained in many cases, the abrasion resistance is very low, andweather- and UV-resistance prove to be insufficient in outdoorapplications.

Much higher abrasion resistances and good barrier orcorrosion-protective properties can be attained with a much lowermaterial expenditure by the application of transparent oxide layers in avacuum. Coating takes place by vapor-deposition, sputtering, or plasmaCVD techniques (G. Kienel: "Vakuumbeschichtung [Vacuum Coating]",Vol. 5,VDI-Verlag, Duisseldorf, 1993). However, inorganic oxide layers producedin this way have a much lower flexibility compared to organic layersproduced by varnishing or laminating. This substantially impairs theinitially very good properties of the vacuum-deposited oxide layersduring use and further processing of the coated films, sheet metals, orplates. Particularly, subsequent stretching or deep-drawing of thecoated materials is hardly possible.

It has already been attempted to combine the high flexibility of organiccoatings with the high abrasion and weather resistance of the oxidelayers. Cited as an example are the so-called called"organically-modified ceramic layers" ("ORMOCER" layers), which areproduced according to the Sol-Gel process and are to be appliedsimilarly to varnish layers (R. Kasemann, H. Schmidt: New Journal ofChemistry, Vol. 18, 1994, No. 10, Page 1117). However, they require alayer thickness similar to those of customary varnish layers.Furthermore, although their resistance to abrasion and weather is betterthan that of varnish layers, it is not as good as that of thinvacuum-deposited oxide layers.

Moreover, it is a known method to produce organic layers with aninorganic oxide component in a way that the organic layers are depositedby plasma polymerization in a vacuum, using organometallic ororganosilicon vapors as monomers for the plasma polymerization, so thata concurrent oxygen admission results in the formation of both metallicoxide and silicon oxide molecules that will be incorporated into thegrowing organopolymeric layer (JP 2/99933). Depending on both themonomers and the proportion of oxygen used, the oxide component in theorganic polymer layer may be varied. In this way, layers of greater orlesser hardness can be deposited that are characterized by both goodabrasion resistance and good barrier and corrosion-protectiveproperties. But a disadvantage of this method is that true-to-qualitylayers can be attained only at deposition rates of a few nanometers persecond. Hence, this technique proves to be unsuitable for the economicalcoating of large areas.

It is known to apply a layer comprising an inorganic component and anorganic component to a substrate for improving gas imperviousness, withthe organic component being non-uniformly distributed in the layer inthe monomer state (EP 0 470 777 A2). The disadvantage of this method isthat the layer is too brittle for further processing, and thevapor-deposition rates attainable with this method are too low.

Also known is a method of ion-assisted vacuum coating, in which a plasmais used to generate ions. In this method, ions are accelerated towardthe substrate through the application of alternatingly positive andnegative voltage pulses, relative to the plasma, between the substrateand a coating source (DE 44 12 906 C1). A disadvantage is that thelayers produced in this manner are too hard for subsequent processing ofthe coated substrate.

It is known to produce oxide-polymer dispersion layers throughsimultaneous evaporation of polymers and metals with two evaporationsources (U.S. Pat. No. 4,048,349). This method is very costly, however,and, in addition, a subsequent thermal treatment must be performed foroxidation.

SUMMARY OF THE INVENTION

It is an object of the invention to create a method for the productionof organically-modified oxide, oxinitride or nitride layers by vacuumcoating that facilitates high deposition rates needed for coating oflarge areas and allows for the deposition of layers that, according tothe intended application, are characterized either by good barrierproperties, corrosion-protective properties or anti-abrasion properties,and possess a flexibility with which the good properties aresufficiently maintained during further processing and use in practice.Extensive homogeneity is intended to be attained over large areas.Moreover, it is an aim of the invention to produce a substrate with acoating that possesses the aforementioned properties. The substratesshould be strip-shaped or sheet-type substrates of arbitrary material.

An essential starting point of the method is the plasma-enhancedreactive deposition of oxide layers known per se, in which the requiredhigh deposition rates as well as the required hardness and abrasionresistance of the layers can be achieved. Surprisingly, it has beenfound that the additional admission of even small quantities of asuitable monomer into the vapor-deposition zone causes an unexpectedlydistinct modification of the otherwise brittle oxide layers toward ahigher flexibility, i.e., an increased ductility and bendability. Inaddition, a higher corrosion-protective effect and a better barriereffect against the diffusion of gases and vapors are attained. To attainprerequisite for attaining these effects it is important that thereactive gas and the monomers are introduced near the substrate and at apreferred direction toward the substrate site to be coated, andthat--together with the evaporated, oxide- or nitride-formingelements--they pass through a plasma zone of high density immediatelybefore they impact the substrate. The admission of reactive gas andmonomers with a preferred direction toward the substrate minimizesunwanted scatter effects, and therefore ensures that the desiredcomponents of reactive gas and monomer molecules at the substratesurface are already obtained with relatively-low gas flows and totalpressures. In this way, a higher packing density of the layer moleculesis attained. The passage through this high-density plasma zone prior toimpact at the substrate has a decisive influence on the layer structureand the resulting layer properties.

Here the molecules and atoms of the evaporated oxide- or nitride-formingelement, as well as the molecules of the reactive gas and the monomers,are excited, and partly ionized, such that they form a denseinorganic-organic molecular network in the growing layer.

The same effect also occurs if, instead of the oxide- or nitride-formingelements such as silicon, aluminum or other reactive metals, theiroxides or suboxides are evaporated, whereby the quantity of the admittedreactive gas can be reduced accordingly. This procedure is of particularadvantage if the corresponding oxides/nitrides or suboxides/subnitridesare less expensive than the oxide- or nitride-forming elementsthemselves, such as silicon dioxide (quartz) compared to silicon. But inmost cases, e.g., with aluminum, the oxide-forming elements are lessexpensive and easier to evaporate than the corresponding oxides orsuboxides.

For particular applications it may also be of advantage if the layerproperties vary gradually over the layer thickness. Withabrasion-resistant layers on plastic film, for instance, it isadvantageous if the layers on the side facing the substrate are lesshard, and therefore better matched to the plastic substrate, whereas itis desirable for the layer surface facing away from the substrate tohave a greater hardness. Such a gradient layer structure can also beobtained if the substrates to be coated is moved over thevapor-deposition zone at a constant speed, and if the admission ofeither the reactive gas or monomers, or the center of the plasma zone,is not located in the center of the vapor-deposition zone but, withrespect to the direction of substrate motion, closer to the beginning orend of the vapor-deposition zone. If these sites are arranged near thebeginning of the vapor-deposition zone, they have a stronger influenceon the layer side facing the substrate, whereas an arrangement near theend of the zone mainly influences the side facing away from thesubstrate, i.e., the layer surface. Generally, a larger reactive gascomponent yields a higher transparency and a greater hardness, but oftenalso a lower flexibility, of the layer. On the other hand, a largermonomer component can increase the flexibility of the layer, althoughthe hardness is somewhat reduced. Finally, an increase in plasma densitycan permit an enhancement of the hardness and adhesion strength of thelayers, and also influence the transparency of the layers. Hence, themean value as well as the local distribution of reactive gas, monomerand plasma density can be used to vary both the mean value and thegradient of the layer properties over the layer thickness within widelimits. The most favorable mean values and local distributions have tobe determined experimentally in accordance with the applicationconcerned.

In accordance with one aspect, the present invention is directed to amethod for producing at least one organically-modified oxide, oxinitrideor nitride layer by vacuum coating on a substrate throughplasma-enhanced evaporation of one of an oxide- and nitride-formingevaporation material, wherein the at least one layer is depositedthrough plasma-enhanced, reactive high-rate evaporation of theevaporation material with use of gaseous monomers and a reactive gascomprising at least one of oxygen and nitrogen, and wherein theevaporation material, gaseous monomers, and reactive gas pass through ahigh-density plasma zone immediately in front of the substrate.

In accordance with another aspect, the present invention is directed toa method for producing at least one organically-modified oxide,oxinitride or nitride layer by vacuum coating on a substrate throughplasma-enhanced evaporation of evaporation material comprisingnitride-forming evaporation material and one of oxide and suboxideevaporation material, wherein the at least one layer is depositedthrough plasma-enhanced, reactive high-rate evaporation of theevaporation material with use of gaseous monomers and a reactive gascomprising at least one of oxygen and nitrogen, and wherein theevaporation material, gaseous monomers, and reactive gas pass through ahigh-density plasma zone immediately in front of the substrate.

In still another aspect, the present invention is directed to asubstrate with an organically-modified oxide, oxinitride or nitridelayer, wherein the at least one layer deposited by plasma-enhanced,high-rate vapor deposition comprises more than 50 wt% of inorganicmolecules and less than 50 wt% of partially cross-linked organicmolecules.

In another aspect, the evaporation material, gaseous monomers, andreactive gas are directed toward the substrate.

In still another aspect, the at least one layer is deposited at acoating rate of at least 10 nm/s. The coating rate may be 20 to 1000nm/s.

In yet another aspect, the high-density plasma zone has a density of atleast 10⁹ cm⁻³. The high-density plasma zone may have a density of 10¹⁰to 10¹² cm⁻³. The high-density plasma zone may have a density of 10⁹cm⁻³ to 10¹⁰ cm⁻³.

In another aspect, the plasma-enhanced, reactive, high-rate evaporationis carried out by one of diffuse arc discharge, pulsed magnetrondischarge, non-pulsed magnetron discharge, and electron cyclotronresonance (ECR) microwave discharge.

In still another aspect, the evaporation material comprises one of metaland metal alloy. The evaporation material may also comprise one ofsilicon and aluminum.

In another aspect, the gaseous monomers comprise at least one ofpolymerizable hydrocarbon, organometallic compound, organosiliconcompound, and organofluorine compound. The gaseous monomers may comprisehexamethylene disiloxane.

In another form, the substrate to be coated is uniformly moved over avapor-deposition zone. The reactive gas may enter the vapor-depositionzone at one of a beginning, a center, and an end of the vapor-depositionzone with respect to the direction of substrate motion. The gaseousmonomers may enter the vapor-deposition zone at one of a beginning, acenter, and an end of the vapor-deposition zone with respect to thedirection of substrate motion. The high-density plasma zone may beexpanded, with respect to the direction of substrate motion, so that thehigh-density plasma zone is located at one of a beginning, an end, andnearly an entirety of the vapor-deposition zone.

In another aspect, the at least one layer comprises more than 50 wt% ofinorganic molecules. The at least one layer may comprise more than 80wt% of inorganic molecules.

In still another aspect, the inorganic molecules comprise one of anoxide, oxinitride, and nitride of one of silicon and metal. The metalmay be aluminum.

In yet another aspect, the partially cross-linked organic moleculescomprise at least one of carbon, silicon, metal, and fluorine.

In another aspect, a concentration of organic molecules in the at leastone layer decreases from a layer side facing the substrate to a layerside facing away from the substrate.

In yet another aspect, a concentration of at least one of oxygen andnitrogen in the at least one layer increases from a layer side facingthe substrate to a layer side facing away from the substrate.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing shows a device for performing the method.

DETAILED DESCRIPTION

The substrate 1 to be coated is a plastic film that is provided with ahighly-reflective metal layer intended for large-area solar reflectorsin solar power stations, and requires a highly-transparent,abrasion-resistant, corrosion-protective and weather-resistantprotective layer. The substrate 1 to be coated is guided, at a constantspeed, from a take-off reel 2 via a cooling drum 3 to an take-up reel 4.At a bottom side of the cooling drum 3, aluminum is evaporated as anoxide-forming element from a series of resistance-heated boatevaporators 5. To evaporate other oxide-forming elements such astitanium or zirconium, or for evaporating oxides or suboxides such asSiO₂ or SiO, it is possible to employ electron-beam evaporators or otherhigh-rate evaporator sources instead of the boat evaporators 5. Twomagnetrons 7 that are pulsed at about 50 kHz in bipolar mode are used togenerate the high-density plasma zone 6 immediately in front of thesubstrate. Arranged below the plasma zone 6 are two nozzle tubes 8, 9for the admission of oxygen as reactive gas, and two nozzle tubes 10, 11for the admission of the monomer hexamethylene disiloxane (HMDSO). Thenozzle tubes 8, 9, 10, 11 are directed toward the site to be coated onthe substrate 1 to ensure reactive gas and monomer and the lowestpossible pressure in the coating chamber.

After setting the desired aluminum evaporation rate with the aid of theboat evaporators 5, and after setting the optimum plasma density in theplasma zone 6 as determined by preliminary tests, the oxygen flowthrough the nozzle tubes 8 and 9 is increased by equal amounts until analuminum oxide layer having the required high transparency has beenattained. The transparency of the deposited layer is measured with theaid of a reflection spectrometer 12. After that, the monomer flowthrough the nozzle tubes 10 and 11 is set at the optimum valuedetermined by preliminary tests. In general, it proves to be suitable toset a higher flow through the nozzle tube 10 than in the nozzle tube 11.Often, the monomer admission will result in a reduced transparency ofthe deposited layer that can be largely compensated by a further oxygenadmission. In the interest of substantial surface hardness of the layer,it is also suitable to admit the additional oxygen mainly through thenozzle tube 9.

What is claimed is:
 1. A method for producing at least oneorganically-modified oxide, oxinitride or nitride layer by vacuumcoating on a substrate through plasma-enhanced evaporation of one of anoxide-and nitride-forming evaporation material, wherein the at least onelayer is deposited through plasma-enhanced, reactive high-rateevaporation of the evaporation material with use of gaseous monomers anda reactive gas comprising at least one of oxygen and nitrogen, andwherein the evaporation material, gaseous monomers, and reactive gaspass through a high-density plasma zone immediately in front of thesubstrate.
 2. The method of claim 1, wherein the evaporation material,gaseous monomers, and reactive gas are directed toward the substrate. 3.The method of claim 1, wherein the at least one layer is deposited at acoating rate of at least 10 nm/s.
 4. The method of claim 1, wherein theat least one layer is deposited at a coating rate of 20 to 1000 nm/s. 5.The method of claim 1, wherein the high-density plasma zone has adensity of at least 10⁹ cm⁻³.
 6. The method of claim 1, wherein thehigh-density plasma zone has a density of 10 ¹⁰ to 10¹² cm⁻³.
 7. Themethod of claim 1, wherein the high-density plasma zone has a density of10⁹ cm⁻³ to 10¹⁰ cm⁻³.
 8. The method of claim 1, wherein theplasma-enhanced, reactive high-rate evaporation is carried out by one ofdiffuse arc discharge, pulsed magnetron discharge, non-pulsed magnetrondischarge, and electron cyclotron resonance microwave discharge.
 9. Themethod of claim 1, wherein the evaporation material comprises one ofmetal and metal alloy.
 10. The method of claim 1, wherein theevaporation material comprises one of silicon and aluminum.
 11. Themethod of claim 1, wherein the gaseous monomers comprise at least one ofpolymerizable hydrocarbon, organometallic compound, organosiliconcompound, and organofluorine compound.
 12. The method of claim 1,wherein the gaseous monomers comprise hexamethylene disiloxane.
 13. Themethod of claim 1, wherein the substrate to be coated is uniformly movedover a vapor-deposition zone.
 14. The method of claim 13, wherein thereactive gas enters the vapor-deposition zone at one of a beginning, acenter, and an end of the vapor-deposition zone with respect to thedirection of substrate motion.
 15. The method of claim 13, wherein thegaseous monomers enter the vapor-deposition zone at one of a beginning,a center, and an end of the vapor-deposition zone with respect to thedirection of substrate motion.
 16. The method of claim 13, wherein thehigh-density plasma zone is expanded, with respect to the direction ofsubstrate motion, so that the high-density plasma zone is located at oneof a beginning, an end, and nearly an entirety of the vapor-depositionzone.
 17. A The method of claim 1, wherein the at least one layercomprises more than 50 wt% of inorganic molecules.
 18. The method ofclaim 1, wherein the at least one layer comprises more than 80 wt% ofinorganic molecules.
 19. A substrate with an organically-modified oxide,oxinitride or nitride layer, as produced by the method according toclaim 1, wherein the at least one layer deposited by plasma-enhanced,high-rate vapor deposition comprises more than 50 wt% of inorganicmolecules and less than 50 wt% of partially cross-linked organicmolecules and wherein a concentration of organic molecules in the atleast one layer decreases from a layer side facing the substrate to alayer side facing away from the substrate.
 20. The substrate of claim19, wherein the at least one layer comprises more than 80 wt% ofinorganic molecules.
 21. The substrate of claim 19, herein the at leastone layer comprises less than 20 wt% of partially cross-linked organicmolecules.
 22. The substrate of claim 19, wherein the inorganicmolecules comprise one of an oxide, oxinitride, and nitride of one ofsilicon and metal.
 23. The substrate of claim 22, wherein the inorganicmolecules comprise metal comprising aluminum.
 24. The substrate of claim19, wherein the partially cross-linked organic molecules comprise atleast one of carbon, silicon, metal, and fluorine.
 25. The substrate ofclaim 19, wherein the partially cross-linked organic molecules comprisehexamethylene disiloxane.
 26. The substrate of claim 19, wherein aconcentration of at least one of oxygen and nitrogen in the at least onelayer increases from a layer side facing the substrate to a layer sidefacing away from the substrate.
 27. A method for producing at least oneorganically-modified oxide, oxinitride or nitride layer by vacuumcoating on a substrate through plasma-enhanced evaporation ofevaporation material comprising nitride-forming evaporation material andone of oxide and suboxide evaporation material, wherein the at least onelayer is deposited through plasma-enhanced, reactive high-rateevaporation of the evaporation material with use of gaseous monomers anda reactive gas comprising at least one of oxygen and nitrogen, andwherein the evaporation material, gaseous monomers, and reactive gaspass through a high-density plasma zone immediately in front of thesubstrate.
 28. The method of claim 27, wherein the evaporation materialcomprises one of silicon dioxide and silicon monoxide.
 29. The method ofclaim 27, wherein the evaporation material, gaseous monomers, andreactive gas are directed toward the substrate.
 30. The method of claim27, wherein the at least one layer is deposited at a coating rate of atleast 10 nm/s.
 31. The method of claim 27, wherein the at least onelayer is deposited at a coating rate of 20 to 1000 nm/s.
 32. The methodof claim 27, wherein the high-density plasma zone has a density of atleast 10⁹ cm⁻³.
 33. The method of claim 27, wherein the high-densityplasma zone has a density of 10¹⁰ to 10¹² cm⁻³.
 34. The method of claim27, wherein the high-density plasma zone has a density of 10⁹ cm⁻³ to10¹⁰ cm⁻³.
 35. The method of claim 27, wherein the plasma-enhanced,reactive high-rate evaporation is carried out by one of diffuse arcdischarge, pulsed magnetron discharge, non-pulsed magnetron discharge,and electron cyclotron resonance microwave discharge.
 36. The method ofclaims 27, wherein the gaseous monomers comprise at least one ofpolymerizable hydrocarbon, organometallic compound, organosiliconcompound, and organofluorine compound.
 37. The method of claim 27,wherein the gaseous monomers comprise hexamethylene disiloxane.
 38. Themethod of claim 27, wherein the substrate to be coated is uniformlymoved over a vapor-deposition zone.
 39. The method of claim 38, whereinthe reactive gas enters the vapor-deposition zone at one of a beginning,a center, and an end of the vapor-deposition zone with respect to thedirection of substrate motion.
 40. The method of claim 38, wherein thegaseous monomers enter the vapor-deposition zone at one of a beginning,a center, and an end of the vapor-deposition zone with respect to thedirection of substrate motion.
 41. The method of claim 38, wherein thehigh-density plasma zone is expanded, with respect to the direction ofsubstrate motion, so that the high-density plasma zone is located at oneof a beginning, an end, and nearly an entirety of the vapor-depositionzone.
 42. The method of claim 27, wherein the at least one layercomprises more than 50 wt% of inorganic molecules.
 43. The method ofclaim 27, wherein the at least one layer comprises more than 80 wt% ofinorganic molecules.
 44. A substrate with an organically-modified oxide,oxinitride or nitride layer, as produced by the method according toclaim 27, wherein the at least one layer deposited by plasma-enhanced,high-rate vapor deposition comprises more than 50 wt% of inorganicmolecules and less than 50 wt% of partially cross-inked organicmolecules and wherein a concentration of organic molecules in the atleast one layer decreases from a layer side facing the substrate to alayer side facing away from the substrate.
 45. The substrate of claim44, wherein the at least one layer comprises more than 80 wt% ofinorganic molecules.
 46. The substrate of claim 44, wherein the at leastone layer comprises less than 20 wt% of partially cross-linked organicmolecules.
 47. The substrate of claim 44, wherein the partiallycross-linked organic molecules comprise at least one of carbon, silicon,metal, and fluorine.
 48. The substrate of claim 44, wherein thepartially cross-linked organic molecules comprise hexamethylenedisiloxane.
 49. The substrate of claim 44, wherein a concentration of atleast one of oxygen and nitrogen in the at least one layer increasesfrom a layer side facing the substrate to a layer side facing away fromthe substrate.